ESAW Searle’s Surface Tension Balance (M-935)

A cast iron base carries a vertical pillar terminating in a horizontal frame. A chrome-plated steel wire is stretched across the frame. A lightweight metal pointer approximately 200mmlong with an adjustable counterpoise is attached to the centre of wire by means of a small clamp. A plastic scale is carried on the end of the arm extending from the torsion frame and is calibrated 5-0- 5 cm. A small mass pan of 40mm dia is attached to the pointer. The sensitivity of the balance is ultimately dependant upon the modulus of elasticity of the torsion wire and the wire supplied.